This invention relates generally to self-propelled vehicles having dual wheel pairs on at least one axle and particularly to small pickup truck and camper vehicles in which the storage of multiple spare wheels is difficult.
It is often found desirable by truck and camper vehicle users to utilize a dual wheel configuration on the rear drive axle of the vehicle. Such dual wheel configurations are well known in the art and, as the name indicates, comprise an axle combination in which a pair of closely spaced wheels are positioned at each end of the axle combination. Generally, all four wheels on the dual wheel axle are directly driven by the axle structure. As a result, increased load bearing capability is provided since all four wheels share the load previously distributed to two wheels. Further, because the traction surface of the dual wheel pair is approximately twice that of the single wheel pair, increased traction is also obtained. In addition, it is often considered aesthetically desirable among truck and camper enthusiasts to provide such dual wheel pairs.
For these reasons, the majority of truck and camper manufacturers make available an option permitting the customer, at the time of purchase, to select the dual wheel configuration. When so provided, these vehicles are available with a standard single wheel configuration on the front two wheels of the vehicle and a four wheel dual pair arrangement on the rear. Because the wheel structure of the wheels used in dual wheel configurations differs from the wheel structure of the wheels used on the front single wheel configuration, the front and rear wheels are not interchangeable. Among other consequences of this difference in wheel construction is the resulting need for individual spare tires and wheels for the front and rear axles.
While such originally manufactured versions having factory installed dual wheel configurations do provide the increased load-bearing, traction and aesthetic accommodations set forth above, they are subject to several limitations. For example, as set forth above, such vehicles must be earmarked for dual wheel construction during the manufacturing process. Because of the general construction techniques of vehicles, it is generally not feasible to convert such systems subsequent to manufacture. Notwithstanding the expense and difficulty of such subsequent conversion, there remains in addition lack of the interchangeability between front and rear wheel hubs creating the above-mentioned need for two spare wheels. While the accommodation of a second spare wheel is of some PG,4 difficulty in larger trucks and camper vehicles, it is often prohibitive for small trucks and campers due to the limited space available.
In view of the foregoing, it is clear, therefore, that there remains a need in the art for a ready means of converting a standard single wheel truck or camper to a dual wheel vehicle with a minimum of work and cost and without creating the need for carrying a second spare wheel.